- Shortest route from Chicago to Rome would be west->east, not east->west.
- 1930s air travel/mail delivery would likely have been by DC-3 (introduced 1935). Early models had a range of 1000 miles, later extended in the DC-3A to 2100 miles. Military C47 A/B aircraft had a 1600 mile range. So you'd have to introduce a few more hops on the map.
- A package would more likely have traveled via ground route, mostly ship. A trans-Asiatic route would be highly unfeasible (or would make for another Indian Jones movie: "Delivery of the Misrouted Journal").
Still, nice touch.